Engine Dies, Strange idle

[dashwitz]

This issue has been bothering me for quite some time now, and its really hard for me to tell what the true issue is, so i'll start with the basics and go from there, hopefully someone can help.

At first the motor would just idle funny, get to a stop light and it would rev up a bit, about 1700-1800 rpm, and as soon as i let off the gas, everything would bog down and the motor would try to stall out. with a careful right foot i could keep her runnin and as soon as i hit highway speeds or put the throttle to 100% she ran great. anything less then full open and she would fight me the whole way.

sadly, i had to take her off the road so now she sits in my garage getting all the attention i can give her in my spare time.

i made a couple videos of the strange idle, if you could take a look and let me know what you think that would be great.

 

[50joe]

I dunno what you may have tried thus far, but I'll tell you where I would start. From the sounds of it, I'm going to assume it is running rich as well. Also going to assume from the dash its a pre-Mass air motor, and still relying on the Map sensor. Make sure the Vacuum line to the map sensor is good and supplying a good constant vacuum to the sensor. If ok, see if you can round up hand held vacuum pump, hook it to the sensor, and make sure it holds vacuum. If it doesn't, its garbage.

If none of that reveals anything, you can try an old trick I use on GM's all the time. shut it off, unplug the connector from the MAP sensor, and start it back up. The ECM will use a default value for MAP. If it smooths out with it unplugged, Thats probably your troubles there. Had a 5.0 mustang hide that problem from me for about 2 weeks before i found it. Hope that helps.....

 

[miesk5]

Run a Self Test;

Self Test by BroncoJoe19 Remember to have engine @ Normal Operating Temperature before doing the KOER portion

Post any Codes found

 

[udallbronco]

on your throttle your can adjust it my grandfather showed me that and that helped my problem out it might help yours